Hearing aid



FIG. 1 is a first perspective view of a hearing aid embodying our design;

FIG. 2 is a second perspective view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a rear view thereof, in which the front end has been angled downward relative to the views seen in FIGS. 3 and 5;

FIG. 5 is a right side view thereof;

FIG. 6 is a front view thereof, in which the front end has been angled downward relative to the views seen in FIGS. 3 and 5;

FIG. 7 is a top view thereof; and,

FIG. 8 is a bottom view thereof. 

We claim the ornamental design for a hearing aid, as shown and described. 